1. Field of the Invention
The present invention relates to a liquid discharge apparatus that discharges a liquid, such as ink, onto a recording medium, to record data using an ink-jet recording method.
2. Related Background Art
Conventionally, for the composition of well known inks used for the ink-jet recording method, generally a soluble high boiler, such as glycol, is added to water as a primary element in order to prevent the drying of the ink and the clogging of nozzles. When an ink of this type is employed for printing on regular paper, the fixing of the ejected ink to the regular paper sometimes is not satisfactory, and an uneven image may occur, which is probably due to the uneven distribution of the loading material and the sizing agent on the surface of a recording sheet. Especially when a color image is to be formed, various colors of ink are ejected and overlap at the same location on the recording sheet before each ink color has been fixed to the paper. Therefore, the ink may smear at the boundary between the different colors, or the ink colors may mix unevenly, so that a satisfactory image can not be obtained.
To resolve the above problem with the ink-jet recording method, there is a well known method whereby, before the ejection of recording ink, the surface of a recording medium is coated with a processing liquid (or a printing enhancement-liquid) in order to improve the image quality.
Disclosed, for example, in Japanese Patent Application Laid-Open No. 5-202328 is a recording method employing an ink compound, which includes at least one chemical dying agent that contains at least one carboxyl, and a polyhydric metal salt solution. According to this method, a polyhydric metal salt solution is applied to a recording medium and then an ink compound is applied thereon to form a preferable image.
Further disclosed in Japanese Patent Application Laid-Open No. 8-193175 are an image forming method for obtaining a satisfactory image, and a printing enhancement-liquid and an ink compound that are used with this method.
For an ink-jet recording apparatus, in order to prevent the clogging of a nozzle and a lack of ink in the nozzle, a so-called suction recovery process is generally performed. In this process, capping means, such as rubber, is brought into contact with a face including a discharging port (hereinafter referred to as a discharge face), which is the nozzle end of a recording head, and pump means that communicates with the capping means aspires ink from the nozzle and establishes a negative pressure in the nozzle in order to accelerate the supply of ink from an ink-tank.
In addition, for the ink-jet recording apparatus, protective capping is also generally performed that caps the entire discharge faces of all the unused recording heads in order to prevent the clogging of nozzles in the recording heads that occurs due to the evaporation of ink, and to protect the surrounding surfaces of the discharge faces when the recording heads are not in use.
In a system that employs the inter-reaction of the processing liquid and the ink compound disclosed in the previous publications, the suction recovery means and the protective capping means must be independently provided for a processing liquid type and for a compound ink type in order to prevent the clogging of a liquid discharge head.
Furthermore, a so-called wiping process is generally performed for the ink-jet recording apparatus in order to remove what ink remains on a discharge face after the suction recovery process for the recording head has been completed, and in order to remove a mist composed of the ink compound that occurs during ink ejection and is affixed to the discharge face. In the wiping process, a wiper (wiping means) made of an elastic material, such as rubber, is brought into contact with the discharge face of the head and is moved relative to the discharge face to wipe the face and to remove the affixed substance.
In the system that employs the inter-reaction of the processing liquid and the ink compound disclosed in the previous publications, independent wiping means must be provided for a processing liquid type and for an ink compound type in order to prevent the clogging of the liquid discharge head.
The present applicant has proposed an epochal method in Japanese Patent Application No. 9-31878, submitted before this application, by which to achieve high image quality when recording on regular paper that does not include a special ink receptive layer for ink-jet recording, and a super high image quality for recording on coated paper that has an ink reception layer. According to this method, a processing liquid discharge head for regular paper, which is provided as standard; a K (black) ink discharge head; and a K, light M (magenta) and C (cyan) ink discharge head are exchanged as needed to acquire an image having a desired high quality.
For the structure where the suction recovery means and the protective capping means are provided independently, at least for the processing liquid system and for the ink compound system that reacts with it, and the structure where different recording heads are exchanged as needed to obtain a high quality image corresponding to the object are to be achieved, the size of the apparatus will be increased, and there is limitation to the saving of the space and reduction of the size. That is, in order to provide a structure where the head for the processing liquid and the head for the ink compound can be set in the same position on a carriage on which the recording heads are mounted and where the suction means and the protective capping means can be independently provided, the suction recovery means and the protective means must be provided for each different recording head type in the direction in which the carriage moves (hereinafter also called the main scanning direction), and the length of the apparatus along the main scanning direction of the carriage will be extended.
Similarly, when the structure where the suction recovery means and the protective capping means are provided independently, at least for the processing liquid system and for the ink compound system that reacts with it, and the structure where different recording heads are exchanged as needed to obtain a high quality image corresponding to the object are to be achieved, the size of the apparatus will be increased, and there is limitation to the saving of the space and reduction of the size. That is, in order to provide a structure where the head for the processing liquid and the head for the ink compound can be set in the same position on a carriage on which the recording heads are mounted and where the wiping means can be provided independently, the wiping means must be provided for each different recording head type in the direction in which the carriage moves (hereinafter also called the main scanning direction), and the length of the apparatus along the main scanning direction of the carriage will be extended.